LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Chevrolet >> 2007 >> Impala SS >> Repair and Diagnosis >> External Pages >> Different car >> Section 558 (Engine Cooling System) >> Diagnostic Information and Procedures >> Scan Tool Data Definitions
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Scan Tool Data Definitions

WARNING: This page is about a different car, the 2007 Saturn Sky. However, it is still accessible from the selected car via links, so may be relevant.
ECT

The scan tool displays -40°C to +151°C (-40°F to +304°F). The engine coolant temperature (ECT) sensor is mounted in the coolant stream. The engine control module (ECM) applies 5 volts to the ECT sensor signal circuit. The sensor is a thermistor which changes internal resistance as temperature changes. When the sensor is cold and the internal resistance is high, the ECM monitors a high signal voltage and interprets it as a cold engine. As the sensor warms and the internal resistance decreases, the voltage signal decreases and the ECM interprets the lower voltage as a warm engine.

FC Relay 1 Command

The cooling fan relay is commanded ON or OFF by the ECM.

FC Relay 2 Command

The cooling fan relay is commanded ON or OFF by the ECM.

FC Relay 1 Circuit Status

The scan tool displays OK or Fault. This parameter indicates the status for the state of the driver circuit for this device.

FC Relay 2 Circuit Status

The scan tool displays OK or Fault. This parameter indicates the status for the state of the driver circuit for this device.